JP5835983B2 - Prestressed reinforced concrete pile with knots - Google Patents

Description

  The present invention relates to a prestressed reinforced concrete pile with a knot, and more particularly to an end structure of a knotted pile made of a pretensioned reinforced concrete structure.

  RC piles, PHC piles, SC piles, PRC piles, etc. are known as types of ready-made concrete piles. Among these ready-made concrete piles, PRC piles have a structure that combines the performance of both RC piles and PHC piles. Yes, it has excellent proof strength against the moment generated in the pile body due to the horizontal force generated during an earthquake.

  On the other hand, the shape of a ready-made concrete pile is known as a hollow cylindrical straight pile defined in JIS A5373 Annex E, an ST pile having an enlarged diameter portion, or a knotted pile having nodes at regular intervals. Among them, a pile with a node having an enlarged diameter portion at a pile head is also manufactured. In addition, as the PRC pile, a so-called copy type PRC pile whose specifications are unified by the Concrete Pile Construction Technology Association is known, but the specifications are not unified in the shape of the ST pile or the knot pile.

  In the pretension type PRC structure, it is necessary to cure and harden the concrete in a state in which the tension material (PC steel material) is pulled after the RC RC bars (hereinafter referred to as axial rebars) are arranged in the pile body. At this time, an interval is generated between the end plate of the pile head or the tip of the pile and the base end of the axial reinforcing bar, and this separated section is structurally a PC structure. Therefore, in such a case, it has been necessary to secure the material and thickness of the reinforcing band to be installed on the pile head or the tip of the pile and to design the cross section so as to satisfy the predetermined performance.

  Moreover, when applying a PRC structure also to a pile with a node, the space | interval section between the end plate of the pile head which will become a PC structure or a pile front-end | tip part, and the base end part of an axial rebar is structurally used. A method may be considered in which a reinforcing band whose length is extended by a predetermined length is used to reinforce the entire length of the RC structure. However, when the reinforcing band is longer than a predetermined length, the one end side of the reinforcing band may bite into the node near the pile head or the tip of the pile, and the integrity of the node may be impaired. Therefore, in the case of a pile with knots, there is a problem that the reinforcing band cannot be made longer than a predetermined length, and the above-described means cannot be adopted.

  Therefore, it is conceivable to newly attach an anchor bar of a predetermined length to the end plate. However, in the PRC structure, a tension member, an axial reinforcing bar, a shear reinforcement bar, etc. are disposed in the pile body. And difficult to secure work space.

  In order to solve the above-mentioned problems, the present invention is easy to work in a narrow work space, but by arranging studs on the end plate by stud welding that can reduce the welding allowance, An object of the present invention is to provide a knotted prestressed reinforced concrete pile in which the integrity of the end plate of the pile tip portion and the axial rebar is ensured and the PRC structure is formed over the entire length.

  In order to achieve the above object, as a first invention, a prestressed reinforced concrete pile with a knot having a diameter-expanded portion on one end side is provided as a first invention, in addition to PC steel, in which an axial rebar is disposed in the pile body, A stud in which a section between the end plate installed in the enlarged diameter portion and the proximal end portion of the axial rebar is located on the outer peripheral side of the PC steel material and the axial rebar, and is installed on the end plate by stud welding It was set as the structure reinforced with a streak.

  Further, in order to achieve the above object, as a second invention, a predetermined amount of a spiral bar is wound around the stud bar, and a spiral bar wound around the axial bar bar, the proximal end of the end plate and the axial bar bar It was set as the structure which reinforces the area which spaces apart from a part with a double helical structure.

  Furthermore, in order to achieve the above object, as a third invention, the stud reinforcement is arranged in parallel with the axial rebar, and the diameter and the number of the stud reinforcement are the same diameter as the axial reinforcement in the pile body, It was set as the structure which is the same number.

  In 1st invention, by setting it as the above structures, a PRC structure is formed over the full length to the edge part of a pile with a node, and the integrity of the end plate of a pile head or a pile front-end | tip part, and an axial reinforcement As a result, the PRC structure in the enlarged diameter portion is advantageous particularly in the axial tensile characteristics of the joint portion.

  And in 2nd invention, by setting it as the above structures, the area which the said end plate which is in a pile body and becomes PC structure and the base end part of the said axial direction reinforcing bar becomes a stud reinforcement. The spiral bar wound around and the spiral bar wound around the axial rebar form a double spiral bar structure, and the structural strength of the section is further enhanced.

  In the third invention, the stud bars are arranged in parallel with the axial reinforcing bars, and the diameter and the number of the stud bars are the same diameter and the same number as the axial reinforcing bars in the pile body. Therefore, it is possible to arrange the fixing stud bars reasonably without difficulty.

FIG. 3 is a half longitudinal sectional view of the prestressed reinforced concrete pile with nodes according to the present invention, with a part thereof omitted. FIG. 2 is an enlarged cross-sectional view taken along line AA in FIG. 1. FIG. 3 is an enlarged partial sectional view taken along line B-B in FIG. 2. It is a half longitudinal section figure which omitted a part of prestressed reinforcing steel concrete pile with a node which has a diameter expansion part in the pile head concerning the present invention.

  Hereinafter, the prestressed reinforced concrete pile with a node concerning the present invention is explained in detail based on the embodiment shown in Drawing 1 thru / or Drawing 4.

  In FIG. 1 to FIG. 3, reference numeral 1 denotes a node pile, and a plurality of node portions 3 (large diameter portions) are formed at predetermined intervals on the trunk portion 2 (small diameter portion) along the longitudinal direction. 5A is an end plate installed on the pile head 1A of the joint pile 1, and a peripheral edge of a reinforcing band 6A wound around the outer periphery of the pile head 1A is connected to the end plate 5A by welding. In the figure, 5B is an end plate installed on the tip 1B of the joint pile 1, and 6B is a reinforcing band wound around the outer periphery of the tip of the pile.

  7 is a PC steel material arranged in a tensioned state on the pile body of the joint pile 1, and is installed over the entire length from the pile head 1 </ b> A of the joint pile 1 to the tip 1 </ b> B. The other end of the PC steel material 7 fixed at one end to the installed end plate 5A extends straight in parallel with the pile axis, and is fixed to the end plate 5B installed at the tip 1B of the joint pile 1.

  Reference numeral 8 denotes an axial rebar disposed concentrically with the PC steel material 7, and a plurality of axial rebars are disposed in parallel with the PC steel material 7, and both end portions 8 </ b> A and 8 </ b> B of the axial rebar 8 are connected to the PC steel material 7. In a state where the concrete C is cured and hardened in a state in which the steel plate is pulled, the concrete is separated from the pile head 1A and the end plates 5A and 5B installed on the tip 1B of the joint pile 1 by a predetermined distance, and this separated section D This is a so-called PC structure in which only the axial reinforcing bars 8 are not provided.

  Reference numeral 9 denotes a stud reinforcement installed by stud welding on the end plate 5A installed on the pile head 1A, which is arranged in parallel along the axial rebar 8 and has a PC structure in the pile body. It covers the portion of the spaced section D and further extends in the other end direction. And the thickness and the number of the said stud reinforcement 9 are set as the structure formed by installing the same number of the same thickness as the said axial direction reinforcing bar 8 in a pile body. In the figure, reference numeral 10 denotes a spiral bar wound around the outside of the axial rebar 8.

  What is shown in FIG. 4 is the other Example of the prestressed reinforced concrete pile 1 with a node which concerns on this invention, and forms the enlarged diameter part 11 in the head 1A side of the pile 1. FIG. And the stud reinforcement 19 is installed in the end plate 15 by the side of the said enlarged diameter part 11 by stud welding, and this stud reinforcement 19 is arrange | positioned at the outer peripheral side of the PC steel material 7 and the axial direction reinforcement 8. FIG.

  As described above, when the stud reinforcement 19 is arranged outside the spiral reinforcement 10, a predetermined amount of the spiral reinforcement 20 is also wound around the outer periphery of the stud reinforcement 19, and the separated section in the pile body and having a PC structure is formed. When the portion D is wound around the outer side of the axial reinforcing bar 8 and the spiral bar 10 is doubled, or the reinforcing band 6A is slightly longer than the length of the stud bar 19 as shown in FIG. To restrain them.

DESCRIPTION OF SYMBOLS 1 Prestressed reinforced concrete pile with a node 1A Pile head 1B Tip part 2 Trunk part 3 Node part 5A ・ 5B ・ 15 End plate 6A ・ 6B Reinforcement band 7 PC steel material 8 Axial reinforcement 9/19 Stud reinforcement 10/20 Spiral reinforcement 11 Expansion Diameter

Claims (3)

In addition to PC steel, when axial rebars are arranged in the pile body, it is a prestressed reinforced concrete pile with a node having an enlarged portion on one end side, and the end plate installed in the enlarged portion and the axial direction The section separated from the base end of the reinforcing bar is on the outer peripheral side of the PC steel material and the axial reinforcing bar, and the end plate is reinforced with a stud reinforcing one end installed by stud welding. Prestressed reinforced concrete pile with knots. A predetermined amount of spiral reinforcement is wound around the stud reinforcement, and a spiral reinforcement wound around the axial reinforcing bar is used to reinforce a space between the end plate and the proximal end of the axial reinforcement with a double helical reinforcement structure. The prestressed reinforced concrete pile with a knot according to claim 1, wherein the prestressed reinforced concrete pile is knotted. The said stud reinforcement is arrange | positioned in parallel with the said axial rebar, and the diameter and number of the said stud reinforcement are the same diameter and the same number as the said axial reinforcement in a pile body, The Claim 1 or 2 characterized by the above-mentioned. Prestressed reinforced concrete pile with knots .

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